Phytosterols and cholesterol

What are phytosterols?

Phytosterols or phytosterols are substances of the sterol group. They occur exclusively as esters and glucosides in plants, and their richest parts are fat. Structurally they resemble cholesterol, which is present in all humans and animals[1].

What are the chemical properties of phystosterols?

Phytosterols belong to the group of sterols, which is a subgroup of steroids. They are all so-called polycyclic (poly-multiple / cyclic-ring) molecules, where the phytosterols are alcohols. They are similar to cholesterol, as well as the sex hormones testosterone and estrogen. It occurs only in plants (phyto - vegetable), and there in the fat-rich parts, such as the seeds[2].

What are the properties and uses of phytosterols?

Fig. 2 The β-sitosterol molecule

Phytosterols are used to lower blood cholesterol levels, while stimulating the production of cholesterol, increasing the total amount in the body, but binding it down, which lowers the cholesterol concentration in the blood. As a negative effect, phytosterols may inhibit the absorption of fat soluble vitamins (e.g., A and E), which should prevent pregnant women, nursing women, children up to 5 years, and those with phytosterinemia from phytosterols. Phytosterols are also used medically to reduce skin irritation and itching. The most common phytosterol we ingest through diet is β-sitosterol at 65%. In cosmetics they are used as emulsifier [3]

What is cholesterol and what does it do?

Cholesterol is an important component of the cell membrane, it increases its strength and helps to guide messenger substances into the cell and out of the cell. The body also converts cholesterol to the sex hormones estrogen and testosterone. The body produces 90% of its cholesterol itself. Increased cholesterol levels can lead to heart attacks and gallstones, so a balanced diet is important to keep cholesterol levels at a healthy level. It has long been investigated whether low cholesterol levels are responsible for a higher degree of violence, poorer memory, increased levels of stress and also the frequency of nightmares[4].



Report on the errors of cholesterol[4]

Scientific article of the Institute of Nutritional Physiology on phytosterols[2][3]


Polysaccharides - What is their purpose in the body?

What are polysaccharides?

Polysaccharides are long chains, called carbohydrates, which consist of smaller simple sugars, so-called monomers. They play an important role for plants and animals, and are partly useful for humans but also partly vital for survival[1].

What are polysaccharides chemically?

Fig. 1 The molecular structure of cellulose

The prefix "poly" states that the molecule is a long chain, with interconnected parts, the monomers (mono means single or one). There are different simple sugars, and all can be linked to polysaccharides. For us humans, glucose, fructose and galactose are the most important sugars. Polysaccharides can be "hetero" which means different, or "homo" which means the same. This designation indicates whether the chain consists of the same or different parts. Cellulose e.g. is a homo-polysaccharide, and hyaluronic acid e.g. is a heteropolysaccharide. Polysaccharides are essential energy sources, and serve the body as energy storage. As so-called glycocalyx they are an important component, the outer surface of the cell membrane. Here they connect the membrane proteins with the membrane lipids, whereby they themselves are directed in the direction of the extracellular (outer) membrane side. The glycocalyx layer makes up the blood group and is an important part of the blood vessel wall, so that its fluids do not "overflow" into the tissue. They are also responsible for cell-cell communication and thus important for the immune system[2].

Fig. 2 The glycocalyx of bacteria

Where are polysaccharides used?

Polysaccharides, in addition to their natural utility as energy storage and membrane constituents, find application in the food industry as e.g. Agar, a vegetable alternative to gelatin for cakes and the like, and in cosmetics as bodying agents, or humectants. They are also used as detergents, drug carriers in medicine and fragrance carriers or fragrance neutralizers[3].

What do polysaccharides do in cosmetics?

Polysaccharides in cosmetics usually provide a gelatinous or creamy consistency, e.g. Xanthan Gum, Gum Arabic or Algin. These binder properties make polysaccharides very useful for natural cosmetics as they are almost all derived from natural sources, are skin-friendly and perform well. Algin is similar in its properties of hyaluronic acid, since it can hold about 100 times its own mass as water, and thus is used as a moisturizer. Deodorants use Destrins, more specifically cyclodextrins, to trap fragrances to neutralize odors, but they can also be used to counteract the effects of storing fragrances and releasing them over a period of time[4].



Scientific article on polysaccharides[2]

Report on the Benefits of Polysaccharides in Cosmetics[4]

Ceramides - The natural skin barrier

What are ceramides?

Ceramides are a subgroup of sphingolipids, and they make up our double lipid layer. It has different types, of which the ceramide I type accounts for most of the horny layer, the outermost layer of skin[1].

What are ceramides chemically?

Fig. 1 The basic structure of ceramides, with sphingosine head, and a fatty acid residue (R)

Ceramides consist of four parts, sphingosine as a "head", a fatty acid as a "base", an amide as a linker and a residue in place of a hydroxide group on sphingosine. This residue can be a hydrogen - ceramide, a saccharide - glycosphingolipid, or a phosphocholine - sphingomyeline. Ceramide I is a fatty acid that binds linoleic acid as a fatty acid, so it has a lack of this fatty acid with a sub-production of ceramide I, and thus an imbalance in the horny layer, serious consequences for health and skin appearance. In addition, it strengthens the hair structure by better bonding the dandruff of the hair strands[2]

This double-lipid layer keeps foreign bodies from penetrating the body and also protects the skin from drying out. Ceramides are formed by first sphingosine with serine and an acyl-CoA, produced by the coenzyme A, it follows the amide esterification with a fatty acid to ceramide. The three best known types of ceramide can be determined by the inclusion angle (α) of the two chains. For example, α = 0 ° Type A, 0 ° <α <180 ° Type B and α = 180 ° Type C. The sphigosine base and the degree of hydroxylation of the Fatty acid decide the further name [3]. The ceramides also play a role in the mode of action of antidepressants [4].

Fig. 2 Detailed illustration of the horny layer

Why are they in cosmetics?

If the body does not produce enough ceramide in the skin, it will cause it to dry out, as well as hypersensitivity (atopic dermatitis) or psoriasis. Ceramide I added to cosmetics can balance this balance of the skin and protect it from the effects of missing ceramide[5].



Scientific article on ceramides in dermatology[2][3]

Scientific article on ceramides in neuroscience[4]

Image sources: Wikimedia Commons, Flickr. All image rights go to the owners of the images.

Vitamins - What are they and how do they help the body?

What are vitamins?

Vitamins are substances our body needs to function. However, they do not make their own class of substance, since they are usually very complex, but very different, even the origin of their name is misleading, vita from - Life and Amine, but not all vitamins are also amines [1]

What are their properties and tasks in the body?

Vitamins contribute to virtually every process in the body. They are important for the utilization of carbohydrates, and thus essential for the energy conversion, the utilization of proteins, for the integration, shaping and transformation, as well as the utilization of minerals, such as copper, iron, zinc, sodium, calcium etc. There are 13 essential Vitamins are known, 11 of which the body can not produce itself (the two exceptions are vitamin D3 and B3) [2]. Plants do not need to eat vitamins via external routes, they can produce all they need themselves. There are vitamins that the body can store, they are fat-soluble and can be stored in the tissues until they are needed, these are vitamins A, D, E, and K. The other vitamins are water-soluble, and so the body can not These are vitamin C and all of the B complex, with the exception of vitamin B12. The vitamins help in addition to the utilization of substances for cell renewal, u.A. in skin as well as hair, nails and muscle tissue. They are also used as active nerve protection and for the correct function of these. A vitamin deficiency can therefore lead to physical problems such as hypersensitivity of nerves, but also to mental health problems such as mood swings. In addition, they act as so-called radical scavengers [3].

What are their chemical properties?

Abb. 1 Vitamin B12 (umgangssprachlich Cobalamin), ein beispiel für die mögliche Komplexität von Vitaminen

The vitamins do not belong to any exact, individual, substance class, they are often quite complex molecules and are therefore quite difficult to categorize. The term "vitamins" only describes essential substances that the body needs for just about anything, but what passes as a vitamin is often unclear, which explains the missing letters and numbers (eg B4, B8 or F, G, H, I and J). Because they are chemically distinct, they perform different, highly complex, biochemical tasks and undergo some enzyme and protein cycles. Fact is, vitamin deficiencies have serious consequences for the body, and cosmetically for the external appearance, such as skin condition and hair. Some vitamins absorb so-called free radicals from the air. Free radicals are atoms or molecules created by atmospheric reactions or ionization by ultraviolet rays, which attack other non-radical atoms and molecules and impose electrons on them to balance their own charge produced by ionization. This process is also called

Abb. 2 Ozonmolekül

Oxidation. Ozone (O3) is partly produced in the air by UV radiation and nitrogen monoxide (NO), which is split again by UV radiation, which produces oxygen (O2) and an oxygen radical (O-). These radicals can attack and damage our organism. They are, for example, the reason why iron rusts in the air, so you can say that we are rusting from the air by radicals. As these radicals oxidize the iron, they partially oxidize our body, and so on. the skin. Radical scavengers such as e.g. Vitamin E or C scavenge radicals, and are oxidized instead of our cells. Although this process turns the vitamins into radicals, they are very slow to react and cause no further damage. The body can also recycle and recycle the vitamins [4].

How do vitamins get into cosmetics and what do they do?

Different plants contain certain vitamins in high concentrations. Vitamins found in natural cosmetics include vitamins A, E and C as well as vitamins B2, B3, B7 and B9. They contribute to a healthy complexion, as they protect the nerves, and thus protect against skin irritation, they contribute to cell renewal, to produce important proteins and enzymes, with collagen and elastin, which are responsible for the elasticity and stability of the skin, and the capture of free radicals in [5].



Scientific Article on Vitamins[1][2][3]

Collagen in cosmetics - anti-aging miracle?

What is collagen?

Collagen is a protein that only occurs in multicellular organisms. It is a structural protein that acts as a scaffold for inelastic fibers such as tendons, ligaments, bones, cartilage, and subcutaneous tissue layers, which are largely composed of a mixture of collagen, elastin, and hyaluronic acid. It accounts for around 30% of all proteins in the human body[1].

How is collagen formed?

Collagen is a so-called triple helix protein, i. That three separate strands of pro-collagens (collagen precursors) come together to form a structure. It is stored in the reticulum, a branched system of channels and cavities for calcium and carbohydrate storage, by enzymes, with the help of ribosomes (complex macromolecules of RNA). Here, first amino acids such as lysine, glycine, proline, hydroxyproline, and some more bound to chains, with the help of coenzymes and ascorbic acid (vitamin C). The resulting single strands of pro-collagene are bound by enzymes with hydrogen and disulfide bridges in their triple helical structure [2].

What are the properties of collagen?

Collagen makes up the majority of the lower skin layer with elastin and hyaluronic acid, and gives structure and strength to bones, cartilage, tendons and ligaments. In the single strands, every third amino acid is glycine, and the three strands are held together by lysine and proline side chains. It has a mass of between 115 and 235 kilodaltons (115-235 kg / kmol), making it a rather large macromolecule. A lack of collagen or elastin causes wrinkles. It also plays a crucial role in biomineralization, involving the process of minerals and trace elements in biomolecules (e.g., calcium and phosphorus in bone and teeth)[3].

How do you get collagen?

Collagen is found in the lower skin layers of farm animals such as pigs and cows, resulting in collagen from cowhides (leather) and pork rinds. Here to 70% from pigskin. There are no non-animal ways to obtain collagen, since neither fungi nor plants nor unicellular organisms are able to produce it [4].

What are the benefits of collagen?

Collagen is a protein and can thereby be denatured, this denatured form is called gelatin. This gelatin is e.g. in food technology as a gelling agent and in pharmacy with as a container in the form of hard and soft capsules. Collagen is used in cosmetics and pharmacy as an anti-aging product, thereby filling the gaps in the tissue causing wrinkles. There are cosmetic products such as creams containing collagen, and concentrates of collagen in the pharmaceutical industry[5].

Is collagen such a miracle cure as it is touted?

There is no doubt that collagen helps to fill the lower layers of the skin and fight against wrinkles, even proven medically. However, this applies only to ingestible concentrates, which are taken orally or intravenously [6], dermal application is the problem of large macromolecules again. Such large molecules can not be absorbed by the skin, thereby reducing or even nullifying their actual effect [7].



Scientific Article on Collagen[1][2][3]

Articles for the production and use of gelatine [4][5]

Hyaluronic Acid in Cosmetics - How Good Does It Really Help?

What is hyaluronic acid?

Hyaluronic acid is a macromolecule, such molecules consisting of several smaller, repeating, parts that consists of disaccharides. It occurs naturally in the human body, as synovial fluid, and important part of connective tissue, cell proliferation (cell growth), cell migration (cell site change), and metastasis (secretion of negative cells, among others, cancer cells). We mainly use the sodium salt of hyaluronic acid[1].

Fig. 1 A monomer, hyaluronan

What are its properties?

Hyaluronic acid is very resistant to mechanical pressure, which is why it does not simply escape from the joint as a gelling liquid. It changes its viscosity proportionally to the pressure of it on it

acts, with a higher pressure means a lower viscosity. It also "sticks" to the joints and is thus additionally protected against leakage from the joint. Hyaluronic acid has a very high water binding capacity, it can bind up to 6 liters of water per gram of hyaluronic acid. Hyaluronic acid can vary greatly in molecular mass, which makes it possible to produce a wide variety of preparations[2].

What is hyaluronic acid used for?

Hyaluronic acid is used as a moisturizer in cosmetics, is a component of eye drops and is used for joint abrasion as a lubricant [3]. It is also an alternative to silicones and plastics in aesthetic medicine, e.g. Modeling and "splashing" lips, calves, facial contours or buttocks. Such hyaluronic acid modeling will last between 6 months and 3 years, depending on the type of treatment and location [4].

Is hyaluronic acid really such a miracle cure?

In theory, hyaluronic acid is a universally applicable agent, with virtually no disadvantages and actually only benefits. For the cosmetic application, however, it is sold as better than it really is. The reason for this is its molecular size. Because hyaluronic acid is a macromolecule, it has an enormous size, weighing between 6000-9000 (6000-9000 kg / kmol) kilodaltons in animal products. Because of this, the molecules are too large to penetrate the skin, leaving most of the effect only on the outermost skin layers and not entering deeper layers. Frequently, the breakdown products of hyaluronic acid are also used, since they have a much lower mass of 50-130 (50 kg / kmol) kilodaltons, but even here only a few of the fragments penetrate deeply enough into the skin [5]. Thus, cosmetics containing hyaluronic acid are only a fraction as good as they are marketed. However, it is not useless as it still provides the uppermost skin layers with water, forming a thin film that protects the lower layers of the skin [6].



Article on hyaluronic acid and its medicinal benefits[2][3]

Scientific Article on Hyaluronic Acid in Aesthetic Medicine[4]

Vegetable oils and fats in cosmetics - how healthy are they?

What are vegetable oils and fats?

Vegetable oils and fats consist of fatty acid esters, so-called triglycerides, as well as secondary substances such as riboflavin (vitamin B2), folic acid (vitamin B9), tocopherol (vitamin E), squalane, terpenes, minerals such as sodium, potassium, magnesium, iron and zinc [1] , as well as essential amino acids such as tyrosine, phenylalanine, leucine and lysine. Whether and how much of these substances are present varies from plant to plant.

What are triglycerides?

Fig.1 Triglyceride, with unsaturated fatty acids (red), saturated fatty acids (blue), and glycerin (black)

riglycerides are so-called esters of fatty acids and glycerin. They are formed by dehydration of molecules and are characterized by the fact that they bind two molecules via an oxygen. These bonds can be cleaved by acidic addition of water or by saponification to produce either the fatty acids or their fatty acid salts [2]. Triglycerides with multiple (polyunsaturated) fatty acids are more fluid, while triglycerides with low to no unsaturated fatty acids are more likely to be solid.

What are fatty acids?

Abb. 2 Lachs hat einen der größten Gehälter an Omega-3-Fettsäuren aller Nahrungsmittel

Fettsäuren sind lange Kohlenwasserstoffketten, welche mindestens eine Carbonsäuregruppe besitzen. Sie sind alle schwache Säuren und keinerlei vergleichbar mit der Säurewirkung von z.B. Salzsäure. Es gibt sehr viele, mal mehr, mal wenig unterschiedlich. Generell kann man unter „gesättigten“ und „ungesättigten“ Fettsäuren unterscheiden, hierbei stehen die Bezeichnungen für Doppelbindungen im Molekül. Fettsäuren ohne Doppelbindungen bezeichnet man als „gesättigt“, Fettsäuren mit Doppelbindungen als „ungesättigt“.

Fatty acids which are polyunsaturated are rather fluid, saturated fatty acids are rather solid [3]. The most common or most found in cosmetics fatty acids are stearic acid, palmitic acid, lauric acid, oleic acid, erucic acid, linoleic acid, arachidic acid and caproic acid [4]. Also, there are fatty acids that the body can not produce itself, yet needs such. the omega-3 fatty acid. It is one of the essential fatty acids of the body that he does not make himself, but on the food intake. They are called omega-3 fatty acids because the last double bond of the polyunsaturated fatty acid, from the carboxylic acid, is 3 carbon behind the last carbon single bond (CC) (This is called omega, since the single bond, as the omega sign in the Greek alphabet last). One such herbal omega-3 fatty acid is alpha-linolenic acid. Omega-3 fatty acids are metabolized for energy, and are used to produce so-called Series 3 prostaglandins, which are responsible for anti-inflammatory. Their metabolites are also needed to regulate blood pressure, control blood clotting and the immune system, and maintain a balanced heart rate [19].

What are the secondary substances in oils and fats?

Secondary substances in vegetable oils and fats include vitamins and minerals, e.g.

-Tocopherol, the vitamin E, which has the task in the body to protect against oxidative stress[5],

-Riboflavin, vitamin B2, which is used in metabolism as a starting material for the production of antioxidant coenzymes[6],

-Squalan, a terpene that softens and smoothes the skin[7].

Minerals are e.g. 

- Potassium, which is important for the skin, kidneys, nerves and brain[8],

- Calcium, which is important for blood, teeth and bones[9],

- Magnesium, which is important for the arteries, heart and muscle[10],

- Phosphorus, which is important for teeth, bones and the brain[11],

- Iron, which is important for the blood, nails and skin[12],

- Zinc, which is a component of many enzymes, and is essential for the metabolism of sugar fat and protein[13]

What are the properties of vegetable oils and fats?

Abb. 3 Aus Kokosnüssen wird das vielseitige Kokosöl gewonnen

The triglycerides are split on the skin, releasing the fatty acids and glycerin. Many fatty acids have anti-inflammatory and protective effects against oxidative stress. In combination, they can firm the skin, strengthen the tissue, strengthen the barrier functions of the skin, protect against water loss, as well as pigmentation spots, counteract both overpigmentation and underpigmentation, and loosen cornification of the skin. They can make the hair softer and smoother and contribute to a naturally beautiful shine, and make the hair healthier overall[14].

Which oils and fats are used in cosmetics?

Frequently used oils are e.g. Jojoba, sesame, argan, avocado, almond, and apricot kernel oils, less exotic, yet often-used oils are e.g. Olive oil and rapeseed oil [15], however, these are just a few of many different oils used. Besides oils, fats and butters are also popular, e.g. Cocoa and shea butter, or coconut oil or coconut oil [16]. They all have different properties, and in the right proportions, they make cosmetics with extraordinary effects.

How are vegetable oils and fats extracted or produced?

Pflanzenöle können auf mehrere weisen gewonnen werden, so z.B. durch das Pressen von Biomasse entweder heiß oder kalt, oder durch Extraktion mit Lösemitteln. Diese Gewinnung und die darauf folgenden Aufbereitungsverfahren bestimmen die Bezeichnung und Inhaltsstoffe der Pflanzenöle. So ist ein Öl welches kaltgepresst (unter 60°C), und nicht raffiniert wurde „unraffiniert“, „kaltgepresst“ und „nativ“, wobei nativ für ein naturbelassenes Öl steht, welches noch so gut wie alle Wirkstoffe besitzt. Ein raffiniertes Öl hat im Gegensatz so gut wie gar keine Sekundärstoffe mehr. Raffinierte Öle sind weitestgehend geruchs-, und geschmackslos, jedoch sehr lange haltbar und universal einsetzbar. Unraffinierte Öle sind dahingegen weniger lange haltbar, haben jedoch ihren typischen, Geruch und Geschmack, sowie den Großteil der Sekundärstoffe behalten. Sie werden jedoch, um die Haltbarkeit zu verlängern gedämpft, wodurch ein Teil der Sekundärstoffe verloren geht. Native Öle sind kaltgepresste Öle, welche im Gewinnungsprozess keinem weiterem Schritt zur Verbesserung der Haltbarkeit durchlaufen. Sie haben noch alle Sekundärstoffe, sind dafür jedoch weniger lange haltbar[17].

Are cosmetics with vegetable oils and fats, better than those without?

Die Frage nach dem „Was ist denn jetzt besser?“ ist zu generell gefragt, schlussendlich kommt es auf jeden selbst an ob oder ob nicht. Fakt ist, dass Kosmetika mit Pflanzenölen, anstelle von Mineralölen, verträglicher und um einiges umweltschonender sind. Aus bestimmten Mischungen von Pflanzenölen kann man selbst auf hoch empfindliche Haut optimal eingehen, eine Flexibilität, welche Mineralölkosmetik nicht besitzt[18]. Möchte man sich selbst, und seiner Umwelt, etwas gutes tun, sind Pflanzenöle eine sehr gute Alternative zu Mineralölen.



List of the most important trace elements and their uses[8][9][10][11][12][13]

Article on the effects of jojoba oil[15]

Article on the effects of almond oil[15]

Article on the effects of coconut oil [16]

Contribution to the effects of vegetable oils on the skin and hair[14][18]

List of the most important vitamins and their benefits[5][6]

Contribution to the chemistry of triglycerides[2]

Scientific article on fatty acids[3][4]

Scientific article on omega-3 fatty acids[19]

Petroleum in cosmetics - What are paraffins and are they harmful?

  What are paraffins?

Paraffins are descendants of the crude oil refinery, more precisely the remains of the distillate. You will find applications in all kinds of disciplines. They can be low or high in viscous liquids, such as solids.

What are paraffins in chemistry?

Hexane molecule (black = carbon, white = hydrogen) Fig. 1

Paraffins are mixtures of acyclic (non-cyclic or aromatic) hydrocarbons having the general formula CnH2n + 2. They can be branched chains or unbranched chains, giving them different properties. The C-C and C-H compounds are relatively strong and are protected by most bases and acids, hence the name paraffin, parum affinis (lat.) = Less reactive. Only halogens, e.g. Chlorine just react with them. [1]

What are their properties?

Dodadecane (C-12) molecule Fig. 2

They are cheap because they are made from petroleum waste. They are chemically quite resistant, and non-toxic, which is why they are used in cosmetics as a base for creams, ointments and others, as well as in medicine as absorption inhibitors. They are well flammable, and will therefore be operated in candles, as well as in grill lighters and hybrid rockets with partly solid and partly gaseous fuels [2]. In addition, they are considered to be relatively biodegradable [3].

What is the problem with paraffins in cosmetics?

It is feared that paraffins from a content of 10% contributes to dehydration of the skin and damage the acid mantle. They are said to prevent the skin from performing its own protective functions that promote wrinkles and impede cell metabolism [4]. However, there is no clear evidence for any of these points, which leaves the negative properties of paraffins controversial. Dermatologists tend to be less likely to face problems with the skin due to paraffins [5].

Are there any alternatives, even if paraffins are considered safe?

Yes there is. There are plenty of alternatives in nature, with no negative but many positive qualities. For example, the avocado oil, or the jojoba oil. In addition to their similar properties, they also contain fatty acids, vitamins and minerals, which additionally do the skin good [6]. They moisturize and contribute to a healthy complexion.

Sources to read:

Stiftung Warentest about paraffin in cosmetics [5]

Degradability of paraffin by bacteria [3]

Scientific article on Paraffin [1][2]

Properties and general information about Jojoba Oil [6]

Beauty Articles on Paraffins in Cosmetics [4]

Image sources: Wikimedia Commons, Flickr. All image rights go to the owners of the images.

Fragrances in cosmetics - how harmful are they?

What are fragrances?

Fragrances are those chemicals that have certain odors, and smell different in different compositions. They are all allergens and irritate the skin. As "perfume", "fragrance", "aroma" and "flavor" these substances are usually called, and we know up to 3000 individual substances, which fall under the category fragrances. They are used in perfumes, scented trees, scented candles and cosmetics. When they spring from nature they are called essential oils.

What are fragrances chemically accurate?

Menthol molecule Fig. 1

Fragrances, or fragrances, are molecules that stimulate different receptors in our nose and therefore smell very differently. They all have molar masses below 300 g / mol, and always consist of a polar, e.g. a hydroxy group, and a non-polar part, e.g. a hydrocarbon chain. Because they are nasally inhaled by us, they are easily volatile, i. E. They evaporate under normal circumstances in part [1]. When we inhale these substances, so-called transmembrane proteins provide, which are responsible for signal transmission under. The smell of a substance depends on which of these proteins stimulates it in combination with each other [2].

Why are they used in cosmetics? 

Fragrances are included in many cosmetics to cover unpleasant odors, or to give a thready product a certain something. In natural cosmetics, they are occasionally included as incidental content or supplement of natural fats and oils. [3]

Vanilla planifolia, seasoning vanilla Fig. 2

What are their good, what are their bad qualities?

As the name suggests, fragrances have a certain scent, or a certain odor. For example, Benzaldehyde bitter almond, vanillin vanilla, lemon citrus and menthol mint / menthol. They usually have a good perceptible odor even at minimal concentrations [4]. Some of them occur naturally, as so-called essential oils, and some of them are synthetically produced [5]. They are all irritating and irritating, and can cause allergies with more pronounced symptoms of irritation, redness, irritation and itching. How strong these symptoms are or whether they occur at all depends on the concentration in the product, and the dispositions of the user. Some people are highly resistant to perfumes and have no symptoms. Some have minimal allergic reactions such as redness or itching. And others are very sensitive about fragrances, they react with severe irritation and irritation, as well as with red, sore spots [6]. Also, they can photosensitize the skin, i. The skin becomes more susceptible to light, which can cause pigmentation disorders [7].

How can you recognize fragrances in cosmetics?

Fragrances have as subcategory the allergens. These are 26 substances that have been subjected to extensive testing and have been confirmed to cause allergies, irritation and irritation. They must be noted from a content of 0.001% for leave-on products, and at 0.01% for rinse-off products. Below these limits no noticeable reaction can be assumed[8].

Are there alternatives ?

No, fragrances have no alternatives, whether in the normal or in natural cosmetics. No known substance replaces the function of these substances without causing many worse side effects. However, it should be said that many people tolerate fragrance as well as problem-free, and have never had any problems with it [9]. For people with allergies, it is important to look at the contents and selectively use products without the problematic allergens, or to leave products with fragrances altogether. It should be said that "perfume free" is not always perfume free. Thus, some fragrances that fulfill a further purpose besides the odor do not qualify as a perfume [10].[9]. Für Menschen mit Allergien heißt es auf die Inhalte schauen und selektiv Produkte ohne die problematischen Allergene nutzen, oder Produkte mit Duftstoffen gleich ganz weg lassen. Hierzu sei gesagt, dass „parfümfrei“ nicht immer Parfüm frei ist. So sind manche Duftstoffe, welche einen weiteren Zweck neben der Geruchsgebung erfüllen nicht als Parfüm einzustufen[10].

Sources to read:

BfR Statement on Fragrances in Cosmetics [8]

Stiftung Warentest Report on fragrance in cosmetics [9][10]

Focus Article on perfumes in cosmetics [6][9]

Scientific article on membrane proteins [2]

Wikipedia [1][3][4][5][7]